The General Packet Radio Service (GPRS) Tunneling Protocol (GTP) tunnel is an important concept of the GTP tunneling protocol, and is used for forwarding signaling messages and service data packets. The GTP tunnel may be categorized into a user plane tunnel and a control plane tunnel, and the tunnel granularity may be based on a User Equipment (UE), Packet Data Network (PDN) connection, a bearer context, or a Packet Data Protocol (PDP) context. A network element applying the GTP protocol identifies a GTP tunnel through an Internet Protocol (IP) address, a User Datagram Protocol (UDP) port number, and a Tunnel Endpoint Identifier (TEID). The TEID is assigned by this network element for a peer network element to use, and the TEID is exchanged between the network elements through a GTP control plane signaling message or a radio side signaling message. The TEID assigned by the network element is also categorized into a user plane TEID and a control plane TEID.
Due to such reasons as equipment overload, a GTP network element may modify a TEID of an established tunnel through a signaling message, and switches a processing module. For example, GTP network element equipment has sub-processing modules A and B, and if the sub-processing module A is overloaded, the GTP network element modifies a TEID of a tunnel established by a user through a signaling message, and switches the tunnel onto the sub-processing module B; for equipment of multiple IP addresses, if IP addresses of interfaces of the sub-processing modules A and B are different, the IP address of the network element is modified while modifying the TEID.
In an existing Evolved Packet Core (EPS) network, a mobility management network element is in charge of such functions as position management, connection management, security authentication, and gateway selection of a mobile UE, and the mobility management network element may be a Mobility Management Entity (MME) or a Serving GPRS Support Node (SGSN). A Serving Gateway (SGW) is a local access gateway of the UE, and is in charge of connection management and data forwarding relevant to an access technology. The UE accesses the network through a local radio access network, and the access network may be a Universal Terrestrial Radio Access Network (UTRAN)/Global System for Mobile Communications (GSM) Enhanced Data rates for GSM Evolution (EDGE) Radio Access Network (GERAN)/Evolved-UTRAN (E-UTRAN).
User plane data packets are directly forwarded between the SGW and an eNodeB, rather than through an MME. However, no direct signaling message interaction exists between the SGW and the eNodeB, establishment/modification/deletion of a GTP user plane tunnel for forwarding the user plane data packets depends on the MME, and the MME is in charge of performing the signaling message interaction between the eNodeB and the SGW, and establishing/modifying/deleting the GTP user plane tunnel between the eNodeB and the SGW.
The SGW carries a user tunnel identifier or the user tunnel identifier and an IP address in a first signaling message, and sends the first signaling message to the MME, the MME carries the user tunnel identifier or the user tunnel identifier and the IP address of the SGW in a second signaling message, and sends the second signaling message to the eNodeB, and subsequently the eNodeB sends relevant data packets to the SGW through a tunnel identified with a corresponding TEID. The MME also stores the TEIDs and the IP address of the SGW.
A direct tunnel mode in SGSN architecture is similar to that in the foregoing scenario. The so-called direct tunnel mode refers to that a user plane tunnel is established between the access network and the SGW, and oppositely, an indirect tunnel mode refers to that a user plane tunnel is established between the SGSN and the SGW.
In such procedures as handover, service request, and re-location, the SGW changes the TEID and/or the IP address, but the eNodeB/Radio Network Subsystem (RNS) cannot obtain the change. The eNodeB/RNS still forwards data packets by using the tunnel identifier and the IP address originally assigned by the SGW, and since the SGW cannot correctly receive/forward the data packets, a data packet loss phenomenon occurs, thereby causing service interruption and influencing user experience. The SGW may return an error indication message to the eNodeB/RNS, and after receiving the message, the eNodeB/RNS deletes corresponding context information, thereby bringing more abnormalities to the network.